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            <h2 class="title" style="clear: both"><a id="txnnowait"></a>No Wait on Blocks</h2>
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      <p>
            Normally when a DB transaction is blocked on a lock request, it
            must wait until the requested lock becomes available before its
            thread-of-control can proceed. However, it is possible to configure a
            transaction handle such that it will report a deadlock rather
            than wait for the block to clear.
        </p>
      <p>
            You do this on a transaction by transaction basis by specifying

            <span>
                <code class="literal">DB_TXN_NOWAIT</code>
                to the
                
                <code class="methodname">DbEnv::txn_begin()</code>
                
                method.
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      <p>
            For example:
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      <pre class="programlisting">    DbTxn *txn = NULL;
    try {
        envp-&gt;txn_begin(NULL, &amp;txn, DB_TXN_NOWAIT);

        ...
    } catch (DbException &amp;de) {
        // Deadlock detection and exception handling omitted
        // for brevity
        ...</pre>
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